1. Field of the Invention
The present application relates to a pressure-sensitive adhesive composition.
2. Discussion of Related Art
In general, the generation of static electricity causes a variety of problems across the entire electronics industry. The static electricity draws fine dust to electronic parts, causing temporary or permanent damage, or malfunction or process delay of the parts in addition to mechanical damage. In order to solve this problem, there is a continuous need to improve antistatic technology with development of the electronics industry.
For example, in manufacture of a liquid crystal display device (LCD), a process of removing a release sheet from a pressure-sensitive adhesive is performed to attach a polarizing plate to a liquid crystal panel. However, static electricity generated in this process affects alignment of crystal displays of the LCD and makes product inspection difficult or causes damage to electronic parts, resulting in an increase in inferior products.
Korean Patent Publication No. 2009-0101761 discloses a pressure-sensitive adhesive composition including an organic ionic salt-based antistatic agent. However, when only an ionic salt is used, a large amount of the ionic salt should be used to reduce the surface resistance of a pressure-sensitive adhesive, which leads to precipitation of ionic salt.
Japanese Patent Publication No. 2005-031282 discloses an optical resin composition which is prepared by blending a metal salt with a resin composition using a monomer having a hydrophilic group such as ethylene oxide. Japanese Patent Publication No. 2005-031282 discloses that the metal salt serves to give conductivity and the hydrophilic monomer serves to reduce a level of electric charge through adsorption of moisture in the air and prevent whitening due to hazing under high temperature/humidity conditions. However, when a hydrophilic monomer is added at a sufficient content to achieve these objects, the physical properties, especially, adhesive strength and durability, of the pressure-sensitive adhesive may be abruptly degraded, and the surface resistance of the pressure-sensitive adhesive may be rapidly increased under high-temperature or high temperature/humidity conditions.